In March 2001 he made his debut in Serie A under Roberto Mancini, before spending periods at Juventus, Modena, Parma and Bologna.

On 18 November 2014, at the age of 33, he became the oldest player to debut for the Italy national football team, playing as a starter in a friendly against Albania.

Right before the Fiorentina bankruptcy, Moretti moved to Juventus in June 2002 for a fee of €2.6 million,[2] and was loaned to Modena to help them avoid relegation.

[5] In the summer of 2004 he was transferred outright to Spanish club Valencia, who had already purchased fellow Italians Bernardo Corradi, Marco Di Vaio and Stefano Fiore.

On 27 August, while remaining on the bench, he was part of the team that won the UEFA Super Cup, beating Porto 2–1.

At the beginning of the following season, on 6 November 2006, in the match against Espanyol, Moretti was seriously injured, damaging his lateral ligament of the knee, forcing him to the sidelines for more than three months.

Despite the injury, the season remained one of the most important on a personal level and as a team, which reached the quarter-finals of the Champions League, defeated only by Chelsea.

The following season, he was still a starter in the Spanish side, which reached the first knockout round of the UEFA Cup, which concludes the year sixth place in the Primera División.

[17] On 26 May 2019, he made his last appearance for Torino and of his football career, coming on as a substitute for Armando Izzo, and helped Torino beat Lazio 3–1 at home, after which he retired from professional football; in total, he collected over 600 career appearances at club level[18][19] Moretti was in Italy's squad in the 1998 UEFA European Under-16 Championship, which the Azzurrini lost to Republic of Ireland in the final.

[5] On 9 November 2014, he was called up to the senior national team by Antonio Conte ahead of a UEFA Euro 2016 qualifying match against Croatia and a friendly against Albania.

[20] On 18 November, he was deployed as a starter in Genoa during a 1–0 win against Albania, becoming, at 33 years, 5 months and 7 days, the oldest player to debut for Italy.